why does devel/cmake's Makefile subst's out compiler optimization?

[Chuck Cranor <chuck%ece.cmu.edu@localhost>]

hi-

     cmake supports different "build types" that control compiler
optimization settings and debugging symbol generation.  the four
standard build types are: Release, Debug, RelWithDebInfo, and
MinSizeRel which are supposed to correspond to:

# /tmp/cmake/bin/cmake --system-information | fgrep CMAKE_C_FLAGS_ | fgrep ==
CMAKE_C_FLAGS_DEBUG == "-g"
CMAKE_C_FLAGS_MINSIZEREL == "-Os -DNDEBUG"
CMAKE_C_FLAGS_RELEASE == "-O3 -DNDEBUG"
CMAKE_C_FLAGS_RELWITHDEBINFO == "-O2 -g -DNDEBUG"
# 

     unfortunately, a cmake compiled with pkgsrc breaks this (note
that all "-O"'s are filtered out):

# /pkg/bin/cmake --system-information | fgrep CMAKE_C_FLAGS_ | fgrep ==
CMAKE_C_FLAGS_DEBUG == "-g"
CMAKE_C_FLAGS_MINSIZEREL == "-DNDEBUG"
CMAKE_C_FLAGS_RELEASE == "-DNDEBUG"
CMAKE_C_FLAGS_RELWITHDEBINFO == "-g -DNDEBUG"
# 

so if you do a -DCMAKE_BUILD_TYPE=Release you don't actually get
any compiler optimization turned on.


I traced this problem down to the pkgsrc Makefile where it does this:

	SUBST_CLASSES+=         flags
	SUBST_STAGE.flags=      pre-configure
	SUBST_MESSAGE.flags=    Fixing compiler flags.
	SUBST_FILES.flags=      Modules/Compiler/*.cmake
	SUBST_SED.flags=        -e 's,-O.,,'

but I don't understand what problem this is trying to fix.

when subst.mk edits the file "work/cmake-3.10.3/Modules/Compiler/GNU.cmake"
that modified GNU.cmake later gets installed in the pkgsrc prefix 
directory and changes the expected semantics of CMAKE_BUILD_TYPE
for anything built with a pkgsrc generated cmake.   this seems wrong?


chuck